#include <iostream>
using namespace std;
int main()
{
 int i,j,temp;
 int a[]={1,3,2,4,6,5,8,7,9},n=9;
 float ave=0;
 cout<<"9???\n";
 for(i=0; i<n; i++) 
 cin>>a[i];
 for(i=0;i<n;i++)
 for(j=i+1;j<n;j++)
 {
    if(a[i]>a[j])
    {
      temp = a[i];
      a[i] = a[j];
      a[j] = temp;
     }
 } 
 for(i=1; i<8; i++)
     ave+=a[i];
 ave=ave/7;
   cout<<ave<<endl;
  return 0;
}
